Tire inflation indicator



' Jam-21,1941. S I -TZ TIRE. IuFLuIok INDICATOR 3 Shoots-Sheet 1Zauzazzcg Filed July 15, 19:9

L. SCHULTZ Jan. 21, '1941.

TIRE INFLATION Iunwxroa Filed July 15, [1939 5 t Av a T 1' Illlllllllllllllllllll I IZ Patented Jan. 21, 1941 UNITED STATES- PATENT"OFFICE 2,2 29,192 Tum INFLATION INDICATOR Laurance Schultz, Gardner,Ill. Application July 15, 1939, Serial No. zam'ze 3 Claims. '(01;177-327) The invention relates to means for enhancing the safety ofautoists by providing means to forewarn of deflation of pneumatic tires,which is a frequent cause of accident and loss by damage to tires as aresult of under-inflation. It is a further aim to overcome difficultiesheretofore experienced in constructing practical and satisfactory meansfor such purposes. An important object of the invention is to enable theaccomplishment of the end in view with a minimum amount of apparatus onthe tire and wheel, and

particularly to so simplify and reduce the weight of such parts thatthey will aifect the balance and function of the wheel in a minimumdegree, and so that they will not be easily deranged incident to shocksand movements of the wheel. A further important object is to evolvemeans for performing the several functions required, and particularly inmeans to show specifically in pounds 20, per square inch the airpressure ineach tire of a vehicle.

It is a further object to combine a novel alarm signal which will insurethat a motor driver will have faulty conditions brought to attentionwith great certainty.

A further important object is to present a system which may include adashunit having simple indicators of the conditions in the severalrespective tires, and which will require a mini mum of space and may belight, inexpensive, and adapted to operate with great certainty, so thatthe motor operator will have before him at all times a full showing ofconditions in each of the tires.

Additional objects, advantages and features. of I invention reside inthe construction, arrangement and combination of parts, involved in theembodiment of the invention, as will appear from the followingdescription and accompanying drawings, wherein 4 Figure 1 is adiagrammatic view of the system. Figure 2 is a view oi the dial panel.

Figure 3 is a. front view of the dash unit fora four-wheel car with thedial plate removed.

Figure .4 is an enlarged rear elevation of one of the tire units. v

Figure 5 is a vertical section thereof on the line 5-5 of Figure 4.

Figure 6 is a diagram of one of the indicator air pressure and alarmcircuits.

Figure '7 is a longitudinal sectional view of the wheel commutator brushmounting.

Figure 8 is a vertical section of a wheel in which my'invention isincorporated.

Figure 9 is a detail enlarged section longitudinally of thewheel-mounted pressure-responsive dial control device.

Figure 10 is a section at right angles to Figure 9.

There is illustrated a system which may include a motor vehicle or.othervehicle having a multiplicity of pneumatic tires but in the specificinstance provides for four tires 15 on the usual four wheels I6 ofconventional manufacture. 10 Each wheel includes a standard rim ll, inwhich 'there is fltted a familiar straight-side pneumatic tire shoe 18,within which an air retaining tube I9 of a usual construction isintroduced. The wheel rim is carried on a pressed metal wheel 15 body 20the form of.which may vary as required, and here includes an impressedcentral portion forming afrusto-conical wall 2| and inner mountingflange 22 adapted to be bolted at 22' to the usual hub flange 23, thehub body 24 of which may conform to approved construction familiar inthe art.

- The hub is mounted in a conventional way, the details of which are notshown, since they comprise no novel feature of. this invention, and themounting may include a usual axle housing 25, having the brake assemblyplate 26, while on the hub flange there is mounted a standard form ofbrake drum 21 close to the plate 26.

- The recessing of the body of the wheel forms a chamber within the wall2i, the inner side of which chamber is closed by the hub and the flange22; while the outer side is closed by the usual removable cover or cap28. 35

The tire air-retaining tube I9 is provided with a standard inflationnipple 29, and in this there is set a valve fitting 30, a lateralconnection including a short hose 3|, leadingto a pressureresponsivedial operating device 32, mounted on 40 the wall. 22 within the wheelchamber. The valve fltting 29 may have in its outer part a standard formof air check valve, the details of which are not illustrated as they arefamiliar in the art. The connection 3i leads from the nipple 45 suretherewithin and to contract when the pressure falls, and in the presentinstance is formally represented by a rubber sac 33 of substantiallycylindrical form encircled by a close-fitting helical supporting spring34, the outer end portion of which is fitted in a. cylinder or sleeve 35adapted to be moved longitudinallyby expansion and contraction of thebellows and carried slidingly in a guide mounting 36, slottedlongitudinally at the upper side. The cylinder is capped over the innerend of the bellows sac as shown. The guide mounting is fixed in a case31 of simple rectangular form attached to the wall 22 of the wheel, andis set between opposite end walls 38, one of which is apertured toreceive'the open end of the sac 33 therethrough, the latter being formedwith an enlargement or flange 39, and a collar 40 being formed on thecase around the sac, externally threaded and receiving thereon athreaded cap 4| by which the flange 39 is compressed and an air-tightseal formed. The cap 4! has a lateral nipple 42 to which the hose 3! isconnected detachably or otherwise, as may be required.

Over the guide 36 in the case 31, there is mounted revolubly asmallpinion 43 for rotation on 'an axis transverse to the path of thesleeve 35, and the sleeve 35 has mounted thereon a rack 44 meshed withthe pinion. concentrically over which is attached at its ends to the endwalls of the case with suitable insulation. Incorporated integrally withthe pinion 43 there is a brush arm 46 having a brush contact 41 thereonbearing on the inner side of the coil. As shown, a lead wire 48 isextended from the left end of the coil in Figure 9, to an insulatedbinding post 49 from which a connection 5| is made with an insulatedcommutator ring 50, on the outer side of the hub flange, 23 within thebrake drum 21. On the brake assembly plate there is mounted aspringloaded brush 52 slidable longitudinally in a sleeve 53 which inturn is longitudinally adjustable in a socket 54 having a set screw 55thereon impinging against the sleeve to holdthe latter in adjustedpositions. The socket 53 is formed with a stem 56 engaged through theplate 26 in a suitable insulating mounting, and an insulated wire 51 isextended therefrom to a respective dash unit indicator for theparticular tire on the wheel described. The construction is similar inthe other wheel units of the vehicle, and respective wires The case 31is preferably in the form of an integral cap or cover stamping 56forming the upper enclosing walls, and a bottom piece 58' to which thecover portion is welded to form a I hermetic seal. Thus, in case offailure of the bellows device, the tire would not be deflated, and

the vehicle could beoperated until a proper repair or replacement of theinstrument could be effected.

The dash installation includes individual indicator devices responsiveto respective currents from the wires 51, and also a sounding alarmdevice responsive to any one of the indicators when a predetermined lowpressure is reached, and will continue as long as the pressure is belowsuch low point, which may be at a sufficiently high point to enable acontinued moderately safe operation of the vehicle with such pressure inthe tire or tires in which it exists, but calling attention to theurgent need for re-infiation, or repair. The dash installation mayinclude a case 60 adapted to be mounted in an approved manner, andincluding four identical scaled dials 6|, on a plate 62, as shown, theupper left one being for the left hand front tire, the upper right handone being for the right hand front tire and the lower two being for theleft and right rear tires, respectively. Each of the dial units beingidentical, only one will be described. It includes a pointer shaft 63,mounted suitably for free rotation on an axis normal to the plane of thedial, and having a pointer needle 64 mounted thereon in proper relationto the dial 6 I, this pointer being extended through the plate 62and'before the dial for ready observation. The shai t is providedintermediately of its length with an armature device 65, consisting of amultiplicity of radial magnetized arms 6661, represented as havingopposite polarity at opposite sides of the shaft. A permanent magnet 63is mounted above the shaft at the left having pole pieces of oppositepolarity extended into close relation to the armature, on such radii asto hold the pointer at a predetermined normal initial position, as shownin Figure 4 (this position, however, corresponds to a high airpressure). This magnet is also represented as having a winding 69, andin practice, has been wound with 800 turns of fine copper wire. Its corepiece 10 may be of iron or steel, arranged radially with respect to thearmature. Attached to its outer end there is an extended combined fieldpi ce and permanent magnet 1| which I have made of steel, extendedinwardly beside the coil and beyond, and being turned inwardly at 12toward the armature 65 on a radius of about 135 degrees, more or less,to the radius of the core 10. This extended end 12 is indicatedconventionally as being the south pole of the magnet normally, and theopposed pole, formed by the inner end of the core 16 as being the northpole of this magnet normally The winding is of such direction that theelectrical magnetic field produced thereby is of the same polarity. Thiswill serve to prevent complete reversal of the magnetic field of thismagnet in the functioning of the adjacent electromagnet 14 to bedescribed, and its field extension, as will subsequently appear.

The magnet 68 is mounted by non-magnetic bracket 13 on the case 66.- Anelectro magnet 14 is mounted above the armature with its core piece 15on a radius at an angle of approximately forty-five degrees to theradius of the core, and supported by a bracket 16 similar to the bracket13, by which the first magnet was mounted. A field extension top bar 11is aflixed magnetically -to the core 15, both of which may be of softiron.

The polarity of this magnet is the opposite of that of the first magnet,in relation to the armature 65, but will only aifectthe armature whenelectrically energized, or while a current isflowing in its windings 18.This winding I have heretofore made of 1,000 turns of fine copper wire.The two windings described are connected at 16' in series. the wire 51leading to the outer end of the winding 18. and the outer end of thewinding 63 being connected by wire 19 to one terminal of a battery orother electrical source, the other terminal of which is grounded on theframe of the motor vehicle. completing the circuit to the case 31.

' The field extension 11 of the electromagnet is projected into closerelation to the upper end of of current will produce further movementsimilarly, and the influence of the field extension the field piece II,so that when thelectromagnet is energized there will be a counter mag--,'netic force tending to cause reversal or reduction in efiectivepolarity in the field of this magnet,'and particularly the pole 12. I

On the shaft 63 there is mounted a brush contact arm 8|, carryingtheswitch brush 82 at its outer end, and at a proper location for thefuncthe electromagnet.

11 from the electromagnet 14 will add an inerement of force that willreduce the eificiency of the poles pf the magnet 68, so that the northpole portion of the armature which was first at the lower side thereof,will come noticeably within the'attractive influence of the pole15 u!The result will be a progressive movement of the armature proportionateto tion to be indicated, a contact sector 83 is mounted with which thebrush 82 will engage as the shaft and arm 8| rotate counter clockwisefrom the high air pressure position as shown in Figure 4. The shaft 63may be grounded at 84 to the frame 25, while from the contact sector 83a circuit is completedthroughthe wire and the .coil 85 of a buzzerformally represented at 86, and lead wire 81, to the battery 80.

the power of the current passed by the rheostat over an arc of degrees,which includes the full length of the scale on the-dial 6|.

It should be understood that a comparatively small amount of electricalenergy will be consumed by the device, owing to the use of small wire inthe winding, as' well as the effect of the resistance 45, and thecurrent consumed in operation of the buzzer will be moderated inproportion to the resistance in the latter.

It will also be understood that the specific construction disclosed ispurely exemplary and that various substitutions, and modifications ofthe construction andarrangements of parts in The wire 85' may becontinued past its connection with the coil 85, as a bus wire connectingtothe sectors of all the units, whereby dangerous lowering of pressurein any tire will operate the buzzer and attract attention to the dial.The sector is located at such position that as the force of currentincreases with move In the operation of the invention, the parts beingassembled as described, and assuming that all ,tires are properlyinflated, the'bellows devices will be projectedto a maximum distance,and the contact 41 will be near thefar end of the rheostat coil 45 fromthe lead-in connection with the commutator ring SI of the wheel unit.The permanent magnet, will hold the armature at a position with thepointer 64 indicating the corresponding high pressure on the dial II.The poles Ill and 12 being on radii of the armature less than degreesapart opposite polarities of the armature will be on a diameter outward10; this angle extending approximately vertical will consequently beover the far portion of the south pole portion of the armature from thepole I. of the magnet 08. As the current builds up in the magnet II therepulsion between the south pole of thelatter magnet and the south poleportion of the armature will cause the lat-' ter to be moved to theleft, rotating the armature counter-clockwise \mtil the increased forceof attaction or magnetic tension the southpol'e or lower end of thepermanently magnetized element 'II and the north pole portion or thearma- Flgure 4. The south pole of the magnet It the system may bemade'without departing from the spirit of the invention except. aslimited by the following claims. V I

It will be appreciated that'whiletheincrease of the force of the magnet68* ll finally entirely overcome the residual magnetism of the permanentmagnet, the eifect oi. current passing through the-winding 69 around itscore 10 will preserve a field, which will prevent any abrupt movement ofthe armature. The windings may,

be varied relatively to attain the desired effects, as'discretion mayindicate. r

1. An indicator device'consisting of a magnetic rotor having parts ofopposite magnetic polarity, on diametrically opposite sides, a pair ofmagnets having rectilinear cores mounted in operative relation to therotor on radii at an magnet.

' than the winding of. the

ture overcomes this tendency. Further build-up angle less than 90degrees, the outer end of the core of one having a field piece connectedthereto extended into operative polar relation to the rotor on a radiusat an angle of more than ninety d nces to the radius of the inner end ofthe same core, and the outer end of the core of the second magnet havinga field piece extended into close operative relation to the outer end ofthe first named core, a pointer carried by the rotor, a dial scaleinoperative-relation to the pointer, and an electrical winding on atleast the core of said second magnet.

2. The structure of claim 1 in which the first named field pieceextension is a permanent magnet, and the said second magnetis an electro3.The structure of claim 1 in which the first named field pieceextension is a permanent magnet, and coil windings on both magnetswhereby both may become electro magnets,.the winding of the said secondmagnet having morejturns first magnet.

LAURANE scnvnrz';

